I wonder... I use the word "renew" may be wrong, since it seems like general V. Bondarev said that the works about Su-47 has never been stopped or stagnated. (Vietnamese is my native language, but I have to use Google Translate to deal with Russian... anyone can speak this language ?)

V. Bondarev wrote:Я думаю, что со временем мы этот самолет увидим, или прототип его, недалеко то время (We will see this plane, or a prototype of it in not a far time.)

(At the moment it has not beer carry out till the end. But the works are not stagnated, the theory are still being developed. I belive when time passes we will see this plane or its prototype.... In the near future, Russian Air Force will introduce the foward-swept wing aircraft. It will also help in improve the training of cadets. We do not abandon this project.)

Su-47 is certainly one of my most favourite fighter, probably because of the impressive foward-swept wing design. But as far as I know, this design is very vulnerable against the air barrier, meanwhile superstrong composite material is not cheap... I am curious to see how the Russians manage to mass produce this piece economically.

I wonder... I use the word "renew" may be wrong, since it seems like general V. Bondarev said that the works about Su-47 has never been stopped or stagnated. (Vietnamese is my native language, but I have to use Google Translate to deal with Russian... anyone can speak this language ?)

V. Bondarev wrote:Я думаю, что со временем мы этот самолет увидим, или прототип его, недалеко то время (We will see this plane, or a prototype of it in not a far time.)

(At the moment it has not beer carry out till the end. But the works are not stagnated, the theory are still being developed. I belive when time passes we will see this plane or its prototype.... In the near future, Russian Air Force will introduce the foward-swept wing aircraft. It will also help in improve the training of cadets. We do not abandon this project.)

Su-47 is certainly one of my most favourite fighter, probably because of the impressive foward-swept wing design. But as far as I know, this design is very vulnerable against the air barrier, meanwhile superstrong composite material is not cheap... I am curious to see how the Russians manage to mass produce this piece economically.

As far as I know the forward swept wing is ideal for subsonic aircraft but in theory it should also be rather more efficient for high speed flight too.

For those not familiar a very simple explaination is that a straight wing generates more life but also generates more drag. The faster you fly the more drag is created so as you get faster a sweep back of the wing can reduce drag while still generating lift.

the main problem is that sometimes the air does not just flow straight over the wing and with very sharply swept wings the air can flow down the sweep. When it gets to the end of the wing the high pressure air and the low pressure air mix and form a huge vortex that generates parasitic drag.

One solution is the wing in ground effect where short broad wings are used on aircraft that fly very close to the ground so the vortex does not form properly and drag is greatly reduced.

another solution is winglets which reduces but does not eliminate the vortex.

Another solution is wing fences but again these do not eliminate the vortex.

the forward swept wing results in the span wise flow heading towards the wing root instead of the wing tip so the wing tip vortex is practically eliminated as a significant force on the aircraft.

careful design allows the spanwise flow to add to lift by flowing over the lifting body fuselage instead of creating a vortex at the wingtip.

The direct result is an enormous reduction in drag, which means the wing can be made smaller and lighter... which further reduces drag etc etc.

The main problem is that in a turn the forces on the wing tend to make it bend upwards which increases the lift and drag and would increase the turn rate which rapidly turns a slow turn into a broken wing.

Modern laminates that are rigid in one direction and relatively flexible in the other promised a forward swept wing strong enough not to break in a turn but flexible enough to promise an active reshapable wing so you can have it flat and low drag for high speed flight and curved and high lift for takeoff and landing. A really active wing could mean no leading edge slats and flaps which would greatly reduce RCS as well.

Personally I would think if they can solve the problems of high speed a forward swept wing offers lower drag and higher lift.

_________________“The West won the world not by the superiority of its ideas or values or religion […] but rather by its superiority in applying organized violence. Westerners often forget this fact; non-Westerners never do.”

― Samuel P. Huntington, The Clash of Civilizations and the Remaking of World Order

@Garry: I am quite curious at how the Russian will solve the problem of high speed. I think the material used to reinforce the wing is not cheap, at least until now.

On paper the problem of high speed does not actually exist. Whether forward or back swept wing... both reduce drag and should allow for high speed flight.

the main problem for back swept wings was the shift in centre of gravity that was rather significant and required an all moving horizontal tail plane to counter the shift.

this is the reason why a flying wing can't exceed the speed of sound normally even though it is very low drag... about as low drag as you could get actually.. even more so if you could get it to fly in stable flight backwards resulting in a forward swept flying wing.

This is not to say a straight wing can't fly supersonically... the F-105 proves that a straight wing can do it, though it is tiny.

the special composite materials used in the high tech wings means they can flex in one direction but not in another.

Another problem is that because of their design and structure you can't mount anything on the wings like weapons pylons or undercarriage folding into wing cavities.

Such limitations would rule out CAS aircraft as although they are subsonic they will need weapon stores on the wings in large numbers to be useful.

Some sort of stealthy long range drone would benefit from forward swept wings... hard to say.

_________________“The West won the world not by the superiority of its ideas or values or religion […] but rather by its superiority in applying organized violence. Westerners often forget this fact; non-Westerners never do.”

― Samuel P. Huntington, The Clash of Civilizations and the Remaking of World Order

Okay so I knew about this aircraft for a while before but thought it was one of the endless killed programs of the 90s. But I came across some stuff that said the program was still on for testing and the likes. I was just wanting to know some details and the likes. Also what is the chance of a fighter being developed with the same wing configure from the research done from this jet. Thanks for everything in advance.

It was part of the MFI and later MFS programs that resulted in determining who would lead the PAK FA programme.

Basically MFI was a programme to find a future medium interceptor... later changed to MFS, which broadened the requirements to be a multi role fighter bomber... They ended up as technology demonstrators, but allowed the Russian AF to decide who should create the next generation Russian multirole fighter.

As we know Sukhoi won and it makes sense for them to continue work on the Berkut as it is currently the worlds only forward swept wing supersonic aircraft AFAIK.

_________________“The West won the world not by the superiority of its ideas or values or religion […] but rather by its superiority in applying organized violence. Westerners often forget this fact; non-Westerners never do.”

― Samuel P. Huntington, The Clash of Civilizations and the Remaking of World Order

GarryB wrote:It was part of the MFI and later MFS programs that resulted in determining who would lead the PAK FA programme.

Basically MFI was a programme to find a future medium interceptor... later changed to MFS, which broadened the requirements to be a multi role fighter bomber... They ended up as technology demonstrators, but allowed the Russian AF to decide who should create the next generation Russian multirole fighter.

As we know Sukhoi won and it makes sense for them to continue work on the Berkut as it is currently the worlds only forward swept wing supersonic aircraft AFAIK.

I think it was a blessing in disguise that the program was halted, because one of the critical flaws within the Berkut's airframe design was how closely aligned the engine exhausts were.

As seen here:

...Increasing the width of the distance between the two engine exhausts by at least '1.5 - 2' meters should not only improve the Berkut's 'instability/maneuverability' when 3-D vector nozzles are applied, it should also facilitate lowering the Berkut's 'RCS' when a 'S-Curve' is applied to the engine intakes (the effect should be rather more effective with the wider spacing), and also should lend more flexibility towards the Berkut's airframe such as adding a larger fuel tank aligned with the spine of the airframe.